The invention relates to a blank stand for receiving and/or temporarily storing at least one tire blank, and to a transport installation for implementing a material flow of tire blanks to tire-production plants, having at least one blank stand.
The manufacturing of tires, for example for vehicles such as automobiles or motorcycles, is an extremely complex process which is composed of a multiplicity of manufacturing and process steps. The reason therefor lies in the complicated construction of the tire, which is composed of a significant number of different individual components. In addition, this multiplicity of components has to be interconnected under the effect of pressure and temperature, by so-called vulcanization.
One of the substantial production steps in the manufacturing of tires is the vulcanization of tire blanks to obtain a finished tire. To this end, the tire blank is placed in a mold that is located within a tire-vulcanizing machine and is subsequently heated to the material-dependent vulcanization temperature and also impinged by a vulcanization pressure inside the tire blank. A suitable heating medium having a respective temperature is incorporated under impingement by pressure in the interior of the tire blank in order for the vulcanization temperature and the vulcanization pressure to be attained.
Not only the finished tire as the final product of the tire-manufacturing process, but also already the tire blank, is a highly complex component that is composed of many semi-finished product elements. As a result of the multilayered construction, the individual components initially and prior to a vulcanization procedure have to be assembled, that is to say that the tire components are supplied to a carcass drum in the correct size in a singularized manner so as to be precise in terms of location, position, and orientation, said carcass drum being located within a tire-construction machine. The tire blank is manufactured and prepared for vulcanization in this manner.
Many of the tire components are available as web- and/or sheet-shaped semi-finished products: various rubber mixtures and caoutchouc-based composite materials, woven textile fabrics or textile cord, respectively, woven steel-belt fabrics, and caoutchouc-sheathed bead cores. Layer servers are in some instances used within a tire-construction machine in order for these web- and/or sheet-shaped semi-finished products to be supplied to the carcass drum.
As a result of the significant number of production steps, production sites are implemented in large sheds and comprise machines, installations, and handling means that are suitable for the individual production steps. These production lines or production centers are supplemented by prestream and downstream equipment for preparing tire components or for post-processing or packing, respectively, the finished tires.
The tire blanks are typically manufactured by tire-construction machines and are initially stockpiled in a store. The tire blanks, depending on demand, are then continuously or discontinuously retrieved from this store which in practical terms serves as a type of first buffer store for the subsequent manufacturing process, said tire blanks being transported to the tire heating presses in order to be vulcanized in the latter.
The tire heating presses in production sheds having a high production capacity are often beside one another in the manner of rows, and the rows of the machines are separated by vehicle-accessible paths. A supply of the tire blanks in the context of a transport system is often performed using rails which are installed in an upper shed region. Transport and holding installations are displaceable in a controlled manner along the rails. According to one variant of a known production sequence, the rails run above the heat presses, and the tire blanks by way of holding installation which are fitted to chains are lowered into the region of the tire heating press.
These transport systems for tire blanks that often operate automatically and on rails below the shed ceiling transport the tire blanks from a buffer station to the tire-vulcanizing machines. The transport trucks herein run on rails up to the respective heating location and load the blank stand of the tire-vulcanizing machine. The blank stand is located at the level of the shop floor and is thus usually level with the tire-vulcanizing machines. For safety reasons a large safety scanner field is required, since a tire by way of a gripping device is automatically rapidly lowered from above onto the floor level. This safety scanner field requires a large shed area and impedes access to the respective tire-vulcanizing machine. Each disruption has to be confirmed by hand, interrupting the supply of further tire-vulcanizing machines.
According to another design of the handling installations, respective transport rails as the displacement base of the loading systems and supply installations run above the displacement paths, so as to be contiguous to the tire-vulcanizing machines and production stations and so as to correspond to the steps of tire manufacturing. The tire blanks to be vulcanized are positioned by handling installations which are equipped with pivot arms and/or arms that are positionable in another manner, in particular with longitudinal outriggers. As a result of the longitudinal outriggers that are significantly shorter in relation to the transport installations that are provided in the region of the shed ceiling, transport installations above the displacement paths are significantly more rigid and thus the more precisely controllable handling system by way of which a very high accuracy is attainable.
One problem in the use of handling installations that are based on transport rails above the displacement paths so as to be contiguous to the tire-vulcanizing machines lies in providing adequate workplace safety. For an efficient tire production, the tire blanks in the operating region in front of the tire-vulcanizing machine, or of the heating press, respectively, have to be lowered in a relatively rapid manner in order for short production times to be implemented. Therefore, there is a significant risk of accidents in this operating region, and the operators that are located in an unforeseen manner in this region could easily be injured. Therefore, visual monitoring systems which lead to an emergency shutdown of the handling installation when a person enters the monitored region during the handling procedures are employed in order to achieve adequate workplace safety. However, an emergency shutdown of this type results in an interruption of production which often can only be addressed again by way of significant delays.